John Cowell now knows what charges he will face in connection with the stabbing death of Nia Wilson at the MacArthur BART station Sunday night. The 27-year-old man was booked on assault with a deadly weapon, violating parole and first degree murder.

John Cowell is accused of killing 18-year-old Nia Wilson and injuring her sister Letifah Wilson at MacArthur BART. He was arrested Monday afternoon at a different BART station in Pleasant Hill.

His first court date has been set for Thursday morning.

Cowell was arrested last night at the Pleasant Hill BART station. Police say he was not armed when they arrested him, and that an anonymous tip led to the arrest. A "925" tattoo on Cowell's neck helped the rider identify him.

They still don't know the motive behind the violent attack that killed 18-year-old Nia Wilson. Police say she and her sister were attacked from behind Sunday night at the MacArthur station in Oakland. They were both stabbed. Nia died from her injuries.

Nia Wilson was just 18 years old when she was killed in an unprovoked stabbing at MacArthur BART station in Oakland. Fighting through sorrow, her friends, family, and the community at large are mourning the teenager who brightened the lives of those she knew, and has inspired many who never got the chance.

A motive remains unclear.

No bail has been set. Cowell will be arraigned Thursday morning.

During a press conference Tuesday, BART police said the stations where the most violent crime occurred were the Richmond, MacArthur, Coliseum, Daly City and San Leandro stations. They encourage riders to stay vigilant, and to have the BART police dispatch number, or the BART Watch app on their smartphones.

Go here for full coverage on the stabbing at Oakland's MacArthur BART station that took the life of 18-year-old Nia Wilson.